Renewables and Energy Technology

Wind turbines, solar panels, home battery storage - if it's discussion about renewable energy you're after, you'll find it here.

Wind turbines, solar panels, home battery storage - if it's discussion about renewable energy you're after, you'll find it here.

battery storage and 3 phase power

rxd
Switched-on

g'day gurus

we have obviously AGL channelled current at home, and 5 Kw of solar on the roof

 

we have 3 phase power in to the house off the grid 'cos we have an oven/induction hot plate set in the kitchen, and a condenser pump in the floor heating system, that both use 3 phase

as i understand it, the rest of the house's kit just draws the single phase (tho' that is an assumption)

 

i am contemplating putting in a storage battery [the Sunverge large looks just the thing]

 

so, the question to which my primitive (matriculation 1964) physics cannot fathom an answer:  how does such a battery storage system cope with, supply current to, kit that draws 3 phase?

 

thanks in advance for, i hope, some enlightenment

Richard D from Shoreham. 

11 REPLIES 11

Re: battery storage and 3 phase power

Powerhouse

Hi Richard, 

 

I too have much the same, 3 phase and 5.5KW solar, I also contemplated battery but first thing to do is ask a really smart person from where you got the solar from, in my case I got a Sunny Boy inverter and it was not cheap compared to a lot of the rubbish being offered today. I also talked direct to the techs at SMA and their reply is as below, the hardware required was quite reasonable at about $2600.00 wholsale but they were reluctant to get involved in the Tesla battery but happy to sell me the SMA hardware needed. I suppose what I am saying is that compatability is a big issue, cost could be significant and at the price of batteries today, still not cheap enough or big enough to cope with rising demand of home use.So, depending on who installed your Solar and the brand, I would start there, and yes I know I did not answer your question because like you, my knowledge is limited, but I will keep any eye out for whoever offers a plausable solution.

 

'You can certainly integrate a Tesla Powerwall in your system with the addition of the new Sunny Boy Storage 2.5: http://www.sma-australia.com.au/products/battery-inverters/sunny-boy-storage-25.html

 

The Sunny Boy Storage 2.5 is the inverter to which your Tesla Powerwall would be connected to, and it will interact with your existing inverter along with the SMA Energy Meter. I have attached a wiring diagram explaining how things would be installed if you go ahead with a SBS2.5 + Tesla Powerwall with your installer.'


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Re: battery storage and 3 phase power

AGL Expert

@rxd wrote:

g'day gurus

we have obviously AGL channelled current at home, and 5 Kw of solar on the roof

 

we have 3 phase power in to the house off the grid 'cos we have an oven/induction hot plate set in the kitchen, and a condenser pump in the floor heating system, that both use 3 phase

as i understand it, the rest of the house's kit just draws the single phase (tho' that is an assumption)

 

i am contemplating putting in a storage battery [the Sunverge large looks just the thing]

 

so, the question to which my primitive (matriculation 1964) physics cannot fathom an answer:  how does such a battery storage system cope with, supply current to, kit that draws 3 phase?

 

thanks in advance for, i hope, some enlightenment

Richard D from Shoreham. 


Richard,

 

Currently the Sunverge battery is a single phase device, as are most energy storage systems sold in australia today. This can still be installed into a three phase system. As you rightly point out most of you household appliances are single phase. AGL would either install the battery on the phase that draws the most power or group your loads so that the solar and battery system can benefit you to the fullest extent possible.

 

Your three phase appliances will be supplied with a mixture of solar power, stored energy in the battery and grid power. Full three-phase systems may be available in the future and these use inverters that can supply energy to all three phases.

 

Please Call AGL Solar on 1300 760 034 and one of our sales consultants can take you through the options.

 

Ed Lynch-Bell

Energy Storage Lead

Re: battery storage and 3 phase power

Powerhouse

Hi Ed,

 

I love that reply, clean and precise, I learn something everyday, lets hope it appeals to your customer!!

 

Rob


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Please remember I am just like you - a customer. If my post has helped, you can click the 'LIKE' button to show your appreciation.

Re: battery storage and 3 phase power

Switched-on

A question for those who are more familiar with the electrical engineering side of things... I don't understand why a battery needs to be associated with a particular phase, in a multi-phase system.

 

Solar panels produce DC power.

Batteries store DC power.

Inverters are where the DC power is turned into AC power.

 

When installed at a site with 3 phase power, with one inverter per phase, why does the battery need to be associated with any phase in particular?

 

Surely it could be installed in parallel with the solar panels, and effectively be hooked up in front of the inverters, and supply DC power to all inverters.

 

Is it just a misunderstanding that people have, due to the expectation that there will be a single inverter (as there is in probably 90% of all residential households)?

 

Or do the DC supplies need to be associated with a specific inverter?

 

Any insights appreciated,

- Steve.

Re: battery storage and 3 phase power

Switched-on

To answer Steve McGahey,

 

there lies the issue Steve. You say "one inverter per phase". That's three inverters and presumably 3 times the cost. Many consumers, including myself are in the position where we have 3 phase to the house but only 1 phase has the import and export facility. If I go to storage, I need to decide on which phase to use because the battery can only supply one phase. The other two will still draw from the grid and therefore attract a bill. I'm waiting for someone to invent an inverter that can create three lots of AC, each 120deg apart. 

 

Cheers Mick

Re: battery storage and 3 phase power

Switched-on

It's not a matter of inventing, just of producing. As the majority of homes are 1-phase, so is the majority of inverter production. Producing 3-phase output is not a technical problem, it's more of a market demand issue.

Re: battery storage and 3 phase power

Switched-on

There is actually a 3-phase battery on the market and is German built and engineered, as well as having almost 3 times as much warranty then Tesla and also uses a safe battery composition. The brand is called Sonnen. 

Highlighted

Re: battery storage and 3 phase power

ZZ
Conductor

House using 3 phase AC (some things wired to one phase, some things wired to all three active legs/lines), grid supplying 3 phase AC (440 V domestic), PV panels producing DC current, a battery system that stores DC, and then you need some smarts.
Approach A: three sets of PV panels each with their own inverter (DC to single phase AC) so that the synchronising between the phases is done by the grid
Approach B: one set of PV panels with an expensive inverter (DC to 3 phase AC)
Approach C: one set of PV panels with an inverter (DC to single phase AC), a DC battery, and a smart box such as the Backup Gateway 2 (made by Tesla) that allows three types of feed-in (single phase, split phase, three phase) and supports up to ten AC-coupled Powerwall batteries, and has nominal AC voltage figures of
(i) 100 V - 240 V for line to neutral (for each of the three active lines/legs)
(ii) 200 V - 440 V for line to line
... I like sound of Approach C

Does anyone know of a fourth way of doing this?

Re: battery storage and 3 phase power

Switched-on

Richard,

I have a degree in Electronic Engineering.  I don't see any reason why a battery would not be able to handle 3 phase.  It makes virtually no difference whether the stove is 1 phase or 3 phase.  The power required would be the same, so it would make no difference to the battery.  Of course, you will need a 3 phase inverter.

Len